Steel square.



Patented lun 5, |900.

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STEEL SQUARE. (Application med No. 1a, 1599,)

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(No Modeh) mi Nonms Pneus co.. PNo-ro-LITMQ. WASHINGTON. D. c.

M2292 25565 j 7% 7%7-44 m. MUJQW UNITED STATES PATENT OFFICE.

ARTEMAS ROBERTS, OF NORMAL, NEBRASKA.

STEEL SQUARE.

SPECIFICATION forming part Of Letters Patent No. 651,057, dated June 5,1900.

Application led November 18, 1899. Serial No. 737,417. (No model.)

To all whom t may concern:

Be it known that I, ARTEMAs ROBERTS, a

citizen of the United States, residing at Normal, in the county ofLancaster and State of Nebraska, have invented new and usefulIinprovements in Steel Squares, of which the following is aspecification.

My invention relates to certain im prove` ments in carpenters steelsquares, the iinprovements'conternplated being,tirst,th esub stitutionupon the blade of the steel square in place of certain figures or tablesusually placed thereon of a conveniently-arranged rafter-table giving induodecimals or feet, inches, and twelfths of an inch the length ofrafters having a certain defined pitch or inclination and a givenhorizontal run, and, second, to give in connection with the raftertablethe figures for the lengths, which, taken on the blade and tongue of thesquare, will give the bevels for the horizontal and vertical cuts forrafters having the given pitch or inclination. I `accomplish theseobjects in the manner illustrated in the accompanying drawing, which isa view of a portion of the blade of a carpenters steel square, showingthe arrangement of my improved rafter-table with the figures giving thehorizontal and vertical cuts for each pitch, as is more fully describedbelow.

Upon the blade A A of a carpenter-s steel square, made in the usualforni, and the place usually occupied by a lumber-table I place a raftertable B B. This table consists of a number of parallel rulings having atthe left end figures C, indicating a certain pitch of inclination, whilealong between the rulings and opposite the usual figures denoting theinches on the outside of the square are given the lengths in duodecimalsor feet, inches, and t'welfths of an inch of rafters having the run ineither feet or inches indicated by said figures and of the given pitchor inclination. In case the run of the rafters is taken in feet we callone inch on the square a f0ot, and the readings of the table will givethe lengths correctly. In case the run is taken in inches the readingsof the table will be in inches, twelfths, and one hundred andforty-fourths of an inch, and the latter may be neglected in most cases.lf the given run consists of feet and inches, the length of the raftermay be taken for the given number of feet and for the given number ofinches, and the two added together will given the entire length.

To illustrate: Suppose the run of a rafter to be twenty-one feet andfive inches (21 5") and the roof to have one-fourth (i) pitch. In thecolumn indicating pitches we find Onefourth, and following the ruling Wefind under the figures 2l on the outside of the square the length Of arafter havinga run of twenty-one feet, (2l,) Which is twenty-three feetfive inches and nine-twelfths of an inch, and under the figure 5 We findthe length five inches and seven-twelfths of an inch of a rafter of fiveinches run, and adding these we get the Whole length of the rafter,which is twenty-nine feet no inches and ten-tvvelfths of an inch, (29 0"10.) In formulating this table I have adhered to the method in commonuse among carpenters of calling the proportion between the verticalheight of the roof and the Width of the building or double the run ofthe rafter the pitch of the rafter. At the right of this table andopposite each of the ruled lines I place the figures, which, taken uponthe blade and tongue of the square, give the bevels for the horizontaland vertical cuts of rafters having the designated pitch or inclination.

Having thus fully described my invention, what I claim is l., Acarpenters steel square made in the usual form and having upon one sideof the blade a table giving the lengths in duodecimals, or feet, inchesand twelfths of an inch, of rafters having a certain defined pitch orinclination and a given horizontal run, the latter being indicated bythe usual figures which indicate inches on the square substantially asdescribed.

2. In combination With a carpenters steel square of the usual form arafter-table, made as shown and described, in which the runs of raftersare indicated by the usual figures denoting inches on the square, Whilethe rafter lengthsare given in feet, inches and twelfths, and having inconnection therewith figures which taken upon the blade and tongue ofthe square will give the bevels for the horizontal and vertical cuts,substantially as set forth.

' AR'FEMAS ROBERTS.

Witnesses:

A. W. WOODS, MARY L. KINSLEY.

